This invention relates to systems or apparatus for supplying webs of paper or other similar material from successively used rolls thereof to an article wrapping machine or any other web-consuming utilization device, and deals more particularly with such a system having the capability of splicing the expiring end of a dispensing roll to the beginning end of a ready roll without slowing down or interrupting the feed to the utilization device and also having the capability of providing a splice having a predetermined location relative to one unit length of web as consumed by the utilization device so that the splice will not fall at a point interfering with the operation of the utilization device or spoiling the appearance or utility of the finished product. It also deals with such a system wherein a repetitive pattern printed on the web of the dispensing roll may be accurately registered with the same pattern printed on the ready roll.
Very basically, the web supply system of this invention is of the general type shown for example by prior U.S. Pat. Nos. 3,645,463 and 3,822,838. Such general systems consist of two reels for supporting respectively a dispensing roll of web and a ready roll of web, a splicer for splicing the expiring end of the dispensing roll to the beginning end of the ready roll, and a festooner or other web storage device located downstream of the splicer and operable to pay out web during the splicing operation to allow the movement of web through the splicer to be temporarily stopped while the splice is made. In prior art systems such as shown by the aforementioned patents, however, the splicing operation is carried out by first braking to a stop the dispensing roll to terminate movement of web through the splicer. During the braking of the dispensing roll the continued pull of the web utilization device increases the tension of the web and this increase in web tension in turn brings the festooner into play to pay out web to the utilization device. Unless some complex photoelectric or other indexing system is provided for controlling the braking of the dispensing roll in response to index marks printed along the length of the web, when the web in the splicer comes to rest, the length of web existing between the splicer and the utilization device is entirely random. This accordingly causes the splice to appear at a random point along one unit length of the web as consumed by the utilization device and prevents controlled location of the splice and controlled registration of any pattern repetitively printed on the web of the dispensing roll with the same pattern on the web of the ready roll. Also, the increase in tension in the web during the splicing operation may cause web breakage problems or problems in the feed of the web to and through the utilization device.
An object of the present invention is, therefore, to provide a web supply system of the general type mentioned having an improved and different form of cooperation between the roll supporting reels, the splicer and the web storage device whereby the pay out of web from the storage device before and during the actual splicing operation is accurately and positively controlled in relation to the feed of web to the utilization device to maintain a controlled displacement of the web through the splicer so when the splicer operates movement of the web through the splicer is stopped with one unit length of the web as consumed by the utilization device having a predetermined position relative to the splicer. Therefore, when the splicer operates on the stopped web the splice made therein will occur at a predetermined point along one unit length of the web and, if necessary, printed matter on the expiring roll may be accurately registered with printed matter on the ready roll. In particular, the improved cooperation is achieved by positively mechanically driving the web storage device in synchronism with the operation of the utilization device. Operation of the storage device is not dependent on the tension in the web passing therethrough. Therefore, this tension may be maintained at a substantially constant value to avoid the possibility of web breakage and to avoid substantial variation in the web tension as supplied to the utilization device. Also, the need for photoelectrical devices and index marks on the web to achieve pattern registration in the course of making a splice is eliminated.
In web supply systems of the general type with which this invention is concerned, after a splice is made it is necessary to remove the spent roll, to install a fresh roll and to condition the system so that when the splicer next operates, it will properly splice the fresh roll to the then dispensing roll to convert the fresh roll to the new dispensing roll. A further object of the invention is accordingly to provide a web supply system of the aforementioned character simplifying the setting up of the system for the making of a subsequent splice after the completion of one splice. In particular, two roll supporting reels are fixed relative to the splicer and each alternately supports either the dispensing roll or the ready roll. The splicer, in turn, is selectively conditionable to accept the roll of either reel as the dispensing roll, the condition selection being made solely by means of a manually operable two-position selector lever without any replacement, adjustment or modification of other parts being required. Additionally, the splicer is so constructed that the preparation and loading thereinto of the beginning end of the ready roll web may be quickly and easily accomplished without great skill or effort. And either a lap joint or a butt joint may be made depending on the loading procedure.
The system of the invention includes, for each reel, a roll diameter sensing means, for initiating a splicing cycle when a minimum dispensing roll diameter is reached, including a pivotal sensing arm having a means at its free end adapted to ride against the periphery of the associated roll. In keeping with the objective of facilitating set up of the system for making a new splice after the completion of one splice, a more particular object of the invention is to provide a means whereby a roll is automatically held to or released from the hub of an associated reel in response to the sensing arm of the associated roll diameter sensing means being either in a position of engagement with the roll or in a retracted position allowing removal and replacement of rolls. That is, the reel hub includes a roll chuck which is conditioned to grip a roll when the sensing arm is in sensing position and which is conditioned to release a roll when the sensing arm is in its retracted position. This also reduces the possibility the operator accidentally leaving the sensing arm in retracted position where subsequent sensing of the minimum roll diameter would not take place.
Other objects and advantages of the invention will be apparent from the following description and from the drawings forming a part hereof.